The most common and most likely answer to this crossword clue is the 6 letter word IBERIA
I've seen this crossword clue in The Times
I
B
E
R
I
A
More clues leading to the result IBERIA
- I live on Rhode Island and a European peninsula
- I breathe the atmosphere, climbing in peninsular region
- A single live broadcast stirred up European region
- Nimble artisan appearing regularly in Spain and Portugal
- Peninsula where river boat is, starts to the north
- One Communist enforcer somewhere in Europe
- Peninsula in Russian region son overlooked
- Huge region needing no introduction, part of SW Europe
- One live broadcast from West European peninsula
- Peninsula in Russian region
Buddy explains!

The straight part
We know that "peninsular region" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case peninsular region = iberia.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.